Reinforced metal can end

ABSTRACT

A metal can end whose central panel has at least two peripheral, radially-separated, concave areas of curvature which provide the end with increased resistance against internal pressure. The panel may also include one or more peripheral steps or convex areas of curvature adjacent the concave areas of curvature.

United States Patent 11 1 1111 3,774,801 Gedde I NOV. 27, 1973 [54] REINFORCED METAL CAN END 3,341,058 9/1967 Martin 220/66 3,288,342 11/1966 [75] Inventor. Erik Gedde, Park Ridge, 111. 2,579,465 12/1951 [73] Assignee. I American can Company, 3,441,170 4/1969 Khoury 220/66 Greenwich, Conn- FOREIGN PATENTS OR APPLICATIONS [22] Filed: Feb. 22, 1971 309,218 3/1966 Switzerland 220 66 1,061,643 7/1959 Germany 220/66 21 Appl. No.: 117,255

' Primary Examiner-Samuel B. Rothberg 220/66, 220/54, 220/72 Assistant Examiner-Stephen Marcus I [51] Int. Cl 865d 7/42 Attorney-Robert Auber, George Ziehmer and [58] Field of Search 220/66, 72, 54, 67 Leonard Kohan [56] References Cited [57] ABSTRACT UNITED STATES PATENTS A metal can end whose central panel has at least two 3,638,825 2 1972 Franck et a1 220/66 p riph r yp concave areas f r 220/66 ture which provide the end with increased resistance 3,417,898 12/1968 Bozek et al.....

------ 220/66 against internal pressure. The panel may also include 2,682,970 7/1954 Brothers, Jr.

11201057 8/ 1936 f 220/66 one or more peripheral steps or convex areas of curva- 2131263.] 3/l943 F et 220/66 ture adjacent the concave areas of curvature. 2,321,408 6/1943 MlllS CI 211. 220/67 3,554,400 1 1971 $616k .31.. 220 54 6 Claims, 5 Drawing Figures REINFORCED METAL CAN END This invention relates to can ends and more particularly to metal can ends for containers of pressurized products such as beer, ale and carbonated beverages.

Can ends, especially those of the easy opening type, i.e., having score lines and lift tabs, are known to sometimes buckle due to internal pressure. The ends buckle among other reasons because the internal pressure causes a pulling force to be exerted on the countersink wall. This force is sometimes strong enough to break the seal between the ends and the can bodies. Another result is that lift tabs protrude from the plane of the can and sometimes thereby cause premature openings and stacking and packing problems.

It has now been found that resistance to internal pressure can be substantially improved and buckling and other low resistance problems can be met by providing can ends with profiles in accordance with this invention.

BRIEF SUMMARY'OF THE INVENTION The metal can end of this invention is for a container of pressurized products and comprises a central panel having at least two peripheral, radially-separated, concave areas of curvature, a depressed, substantially U- shaped reinforcing groove contiguous with and peripheral to said panel, and a contiguous, peripheral, substantially upwardly-extending countersink wall which merges with and terminates in a peripheral, arcuate flange for attaching the end to a container body. The invention covers both the can end by itself and as secured to a container body. The peripheral portion of the central panel between the concave areas of curvature can be substantially planar. The central panel can include one or more peripheral, convex areas of curvature adjacent the concave areas of curvature. In a preferred embodiment, one convex area is included between the concave areas of curvature.

REFERRING TO THE DRAWING FIG. 1 is a top plan view of a can end prior to its attachment to a can body;

FIG. 2 is an enlarged sectional view taken substantially along line 2-2 of-FIG. l; I

FIG. 3 is a sectional'view, taken substantially along line 2-2 and through a can body, showing the end secured to a can body;

FIG. 4 is an enlarged sectional view taken along line 4-4 in FIG. 1; and

FIG. 5 is an enlarged sectional view of a preferred embodiment of an end as it would appear if taken along line 4-4 of FIG. 1.

Referring to the drawing in detail, FIG. 1 shows an easy open can end generally designated having a circular central panel 12 surrounded by a contiguous, pe-

ripheral, substantially planar, reinforcing central panel portion 14 within defining flexed areas 13 and 15 (on opposite sides of respective concave areas of curvature's A and B in FIG. 2), in turn surrounded by a contiguous peripheral, recessed, U-shaped reinforcing groove 16. Groove 16 merges with an outer peripheral countersink wall 18 which in turn merges with and terminates in a contiguous peripheral arcuate flange20. A sealing material, (34 in FIGS. 25), can be adhered to the underside of arcuate flange for secureing the 'can "end to a can body (36 in FIG. 3). Extending generally radially from the center'of panel 12 is a removable or tear-out portion 22 completely enclosed within and defined by an endless score line 24. While tear-out portion 22 is illustrated, as being in the shape of a tear drop, it can be of any other suitable shape. Secured to tear-out portion 22 at its innermost end by means of peened-over embossment or rivet 28, is lift tab 26, and, adjacent and substantially parallel to tear-out portion 22 are smile beads 30 and 32 for absorbing excess can end material from around tear-out portion 22 and for reinforcing the center panel against distortion in the area surrounding tear-out portion 22 when it is being removed. While can end 10 is circular, itis understood that it may be of any suitable shape, depending of course on the shape of the can body. It is also understood that the combination of easy opening features shown in FIG. 1 are merely exemplary and that any suitable easy opening or other features of various sizes and shapes can also be used in relation to the can end of this invention. FIG. 2 is an enlarged section view of the can end taken substantially along line 2-2 in FIG. 1. FIG. 2, is a profile of the end showing central panel 12, and specifically shows on the right side of the figure, diagonal reinforcing central panel portion 14. Central panel 12 can be substantially planar or can be concavely-domes as preferred and shown. In either case all portions, more specifically, all peripheral or substantially peripheral radially-separated portions of the central panel extend in either a planar or upward direction from U- shaped reinforcing groove 16 toward a central area of the central panel, for example the area adjacent rivet 28. The preferred domed version is given its shape during manufacture, i.e., pre-domed, rather than being substantially planar and taking on its domed shape due to container internal pressure. Reinforcing central panel portion 14 is defined by flexed areas 13 and 15 opposing respective peripheral, radially-separated, concave areas of curvature A and B. The flexed areas result when the concave areas A and B are formed. Radially separated" here means that each area of curvature, for example A and B, is adjacent the tip of a separate radius of different length extending from a common point located substantially in the center of domed central panel 12. Thus, the radius extending to B is longer than the one extending to A. As shown in FIG. 1, it can therefore be seen, and it is to be noted that comparable points along area of curvature A, or B, have radii of equal length which extend from the common point substantially in the center of central panel 12. It is to be noted and distinguished that each of these concave areas of curvature is formed by a circumferential arc of curvature, each are being formed by its own relatively short radii extending from a common point below central panel 12. Although more than two such concave areas of curvature can be utilized, it has been found that a substantial improvement in the amount of resistance to internal pressure, i.e., buckle resistance, is obtained when at least two such areas are utilized.

For example, whereas standard steel can ends have anaverage buckle resistance of from about to psi., the can ends as shown in FIGS. 2-4 have an average buckle resistance of about 94 to psi. As will be explained, this increase is even greater when there is also included one or more peripheral steps or convex areas of curvature (See FIG. 5). I

FIG. 3 is another enlarged sectional view of the can end of FIG. 1 taken substantially along line 2-2, and

shows can end joined and hermetically sealed and secured to can body 36 by the interfolding of arcuate flange 20 and can body flange 38 to form conventional double seam 40. It is understood that the lower end of can body 36 is suitably closed, for example, by an integral end, if the body is of the drawn or extruded type, or by a separate end seamed thereto, if the body is initially formed with an open bottom:

FIG. 4 is an enlarged sectional view of the can end taken substantially along line 4-4 of FIG. 1, showing two concave areas of curvature A and B, substantially planar central panel portion 14 therebetween, reinforcing groove 16, countersink wall 18, arcuate flange 20 and sealing material 34. Since it is often difficult to determine where central panels terminate and where reinforcing grooves begin on can end profiles, central panel 12 of this invention will be understood to extend down to about point T where its downwardly extending portion, considered as a tangent, meets the arc of curvature of U-shaped reinforcing groove 16.

FIG. 5 is another enlarged sectional view, this one being a preferred embodiment as would be seen sub stantially along line 44 were the preferred version to replace the end shown in FIG. 1. FIG. 5 shows the two concave areas of curvature A and B having a flexed area or peripheral convex area of curvature V therebetween. More than one of such convex areas of curvature may be provided adjacent, i.e., radially on either side of as well as between areas A and B. The same applies if there are more than two concave areas of curvature.

As with areas A and B, the peripheral step or convex area of curvature C, opposite convex area of curvature V, is radially separated, and is adjacent the tip of its own separate radius extending from a point located, e.g., in the center of central panel 12. And, similar to areas A and B, convex area of curvature C is part of a circumferential are formed by relatively short radii extending from a point above domed central panel 12. While the step shown in the embodiment of this invention is arcuate, it can also be angular. Concave areas of curvature A and B in the bottom surface of the panel convex 13' and 15' on the opposing surface.

It has been found that providing a step or convex area of curvature in the aforementioned manner between concave areas of curvature A and B, increases buckle resistance over the standard steel end by from about 8 to 15 psi. Thus, as opposed to the standard steel average buckle resistance of from about 90 to 107 psi, the stepped profile obtains buckle resistance of from about 90 to 120 psi, and is the preferred embodiment of this invention.

While the can end profile of this invention incorporating at least two radially-separated peripheral concave areas of curvature obtains increased buckle resistance when utilized on a domed central panel, it is to be understood that advantageous increases can also be obtained when the profiles of this invention are utilized in relation to central panels having other profiles, e.g., those which are substantially planar.

Aside from increased buckle resistance, the can end profiles of this invention obtains other advantages such as increased container capacity of about 0.21 fluid oz.

over containers having conventional, planar surfaced central panels. Another advantage is that because the wall of reinforcing groove 16 that merges into central panel 12 is not, as usual, sharply upwardly extending but is merely diagonal and sloping, less metal is used to form the area where the groove and panel meet. This available metal can be used toprovide longer arcuate flanges for improved interfolding and double seaming. Still another advantage is that sounds called beer can crickets often occurring after beer. cans are opened, can be essentially eliminated.

While the presently preferredembodiments of this invention have been hereby illustrated and described, it will be understood that the invention may be still otherwise variously embodied within the scope of the claims which follow.

What is claimed is:

l. A metal can end for a pressurized container comprising:

a rigid central panel having at least two peripheral, radially-separated, concave areas of" curvature, a planar, upwardly-extending reinforcing central panel portion between said concave areas of curvature, a depressed, substantially U-shaped reinforcing groove contiguous with and peripheral to said panel, and a contiguous, peripheral, substantially upwardly extending countersink wall which merges with and terminates in a peripheral arcuate flange for attaching said end to said container, all portionsof said central panel being such as to extend in an upward direction from said reinforcing groove toward a central area of said central panel, and the portion of said central panel radially inward of said concave areas of curvature being of a pre-domed configuration.

2. The metal can end of claim 1 wherein said can end is secured to said container body by a double seam formed by said arcuate flange of said end being interfolded with a peripheral container body flange.

3. The metal can end of claim 1 wherein said metal is steel.

4. A metal can end for a pressurized container comprising a rigid central panel having at least two peripheral, radially-separated, concave areas of curvature, a peripheral, convex area of curvature between and radially-separated from said concave areas of curvature, a depressed, substantially U-shaped reinforcing groove contiguous with and peripheral to said panel, and a contiguous, peripheral, substantially upwardlyextending countersink wall which merges with and terminates in a peripheral arcuate flange for attaching said end to said container, said convex area of curvature being in the form of a step no portion of which extends in a downward direction, and the portion of said central panel radially inward of said concave areas of curvature being of a pre-domed configuration.

5. The metal can end of claim 4 wherein said can end is secured to said container body by a double seam formed by said arcuate flange of said end being interfolded with a peripheral container body flange.

6. The metal can end of claim 5 wherein said metal is steel. 

1. A metal can end for a pressurized container comprising: a rigid central panel having at least two peripheral, radiallyseparated, concave areas of curvature, a planar, upwardlyextending reinforcing central panel portion between said concave areas of curvature, a depressed, substantially U-shaped reinforcing groove contiguous with and peripheral to said panel, and a contiguous, peripheral, substantially upwardly extending countersink wall which merges with and terminates in a peripheral arcuate flange for attaching said end to said container, all portions of said central panel being such as to extend in an upward direction from said reinforcing groove toward a central area of said central panel, and the portion of said central panel radially inward of said concave areas of curvature being of a pre-domed configuration.
 2. The metal can end of claim 1 wherein said can end is secured to said container body by a double seam formed by said arcuate flange of said end being interfolded with a peripheral container body flange.
 3. The metal can end of claim 1 wherein said metal is steel.
 4. A metal can end for a pressurized container comprising a rigid central panel having at least two peripheral, radially-separated, concave areas of curvature, a peripheral, convex area of curvature between and radially-separated from said concave areas of curvature, a depressed, substantially U-shaped reinforcing groove contiguous with and peripheral to said panel, and a contiguous, peripheral, substantially upwardly-extending countersink wall which merges with and terminates in a peripheral arcuate flange for attaching said end to said container, said convex area of curvature being in the form of a step no portion of which extends in a downward direction, and the portion of said central panel radially inward of said concave areas of curvature being of a pre-domed configuration.
 5. The metal can end of claim 4 wherein said can end is secured to said container body by a double seam formed by said arcuate flange of said end being interfolded with a peripheral container body flange.
 6. The metal can end of claim 5 wherein said metal is steel. 